Architects and landscapers understand the importance of providing areas of shade to shield occupants from the sun's rays. Shade structures enhance the ability to use outdoor spaces during the heat of the day. FIG. 1 shows an example of a shade sail 10. Shade sails 10 are created by tensioning a membrane 12, often a fabric, between several spaced apart support posts 14 or mounting points. Shade sails 10 are often used because of the elegant appearance created by the membrane 12 as it is stretched to form a non-planar three-dimensional shape between the support posts 14. The membrane 12 itself can be provided in a variety of shapes and patterns stretched between three, four, or even more support posts 14.
The membranes 12 of current shade sails 10 must be constructed with sufficient strength to accept the tensioning forces applied at each support post 14 while extending over unsupported spans of several feet, often ten feet or more. By the nature of their use outdoors, the presently used membranes 12 are intended to avoid premature degradation in both strength and appearance often caused by exposure to light from the sun.
A representative membrane 12 currently available for shade sails 10 are fabrics such as Synthesis AF230™ sold under the Coolaroo® Brand by Gale Pacific. This fabric is a 3-bar warp knit fabric formed entirely of UV stabilized high density polyethylene (HDPE). While the knit HDPE fabrics meet many of the structural characteristics for suitability as a shade sail, HDPE yarns provide a synthetic plastic appearance. Therefore, there remains a need for alternative fabrics suitable for providing shade in outdoor environments.